1. Field of the Invention
The present invention relates to an occupant protection system including a seat belt for restraining and protecting the occupant.
2. Related Technology
A three-point occupant protection system provided in conjunction with a seat of a vehicle is a system for restraining and protecting an occupant upon the collision of the vehicle, and comprises a seat belt (webbing), a retractor, and a buckle. A retractor is disposed, for example, at the lower part of the center pillar, at the side of the seat, and winds one end side of the seat belt around a winding shaft and retracts the seat belt internally with the biasing force of a spiral spring, and, when the seat belt is not being worn, houses the seat belt in such retracted state. The other end side of the seat belt is folded back at a through-anchor disposed at the upper part of the center pillar, and is rotatably fixed by a plate-shaped belt position changing member provided at the lower part of the center pillar. Moreover, a tongue plate is inserted through the seat belt midway, and the tongue plate is configured to be secured to the buckle disposed on a side that is opposite to the refractor across the seat.
The occupant can wear the seat belt by pulling out the housed seat belt by pulling the tongue plate and securing the seat belt via the tongue plate to the buckle provided to the side of the seat.
Meanwhile, with the foregoing occupant protection system, in a state where the occupant is not wearing the seat belt immediately after getting into the car and sitting down, since the tongue plate is positioned at the rear of the seat, the occupant is required to twist one's body backward to pull out the seat belt.
Patent Document 1, Japanese Patent Application Publication No. 2009-40323, discloses an occupant protection system which enables the occupant, after sitting down, to easily wear the seat belt without having to twist one's body as a result of adopting a configuration of turning the belt position changing member frontward. Specifically, the belt position changing member is provided with a biasing member for turning the belt position changing member frontward, and the retractor comprises a motor for rotating the winding shaft in the normal/reverse direction, and a clutch. When the motor is driven via normal rotation, the clutch is operated and the drive force of the motor is transmitted to the winding shaft, whereby the seat belt is wound. When the motor is driven via reverse rotation, the clutch is released, and the drive force of the motor is not transmitted to the winding shaft. When the occupant gets into the car and wears the seat belt, the motor is driven via reverse rotation, and the belt position changing member is turned frontward based on the biasing force of the biasing member. Thus, the tongue plate moves toward the front of the seat, and the occupant can wear the seat belt without having to twist one's body backward. Moreover, when the occupant gets out of the car, the motor is driven via normal rotation to wind up the seat belt and turn the belt position changing member toward the rear of the vehicle, whereby the seat belt is retracted.
Nevertheless, with the occupant protection system described in Patent Document 1, since the turning of the belt position changing member is controlled by controlling the rotating speed of the motor, if the seat belt gets caught on the occupant's arm or the like while the belt position changing member is being moved to the rear position of the vehicle, there is a problem in that the occupant is strongly restrained by the seat belt and experiences a feeling of discomfort.
Moreover, while a configuration of detecting the motor current and stopping the rotation of the motor can also be considered, when the motor current is equal to or higher than the threshold current, there is a problem in that the normal rotation drive of the refractor is ended even though the retraction of the belt position changing member is not complete.
In addition, when the seat belt is to be removed, since the motor will not be driven via reverse rotation until the occupant gets off the car, the clutch remains in an ON state when the seat belt gets caught on the occupant's arm or the like and, therefore, there is a problem in that it becomes difficult to pull out the seat belt, and the occupant will experience a strong sense of discomfort.